In the medical field, and in the area of wound care particularly, it is well-established that many factors, including the amount of moisture present at a wound site, affects how quickly a wound will heal. Generally speaking, having an excessive amount of moisture present at a wound site, especially when combined with the warm environment provided by the body, leads to undesirable bacteria growth and production of protease enzymes in the wound. Such growth can cause further damage to healthy cells and delay the healing process. However, insufficient moisture at the wound site can cause eschar (scab) formation and scarring and may cause the wound care device, or medical dressing, to adhere to the wound. If the dressing adheres to the wound, subsequent removal of the dressing may cause undue discomfort to the patient as well as disrupt newly granulated tissue. Infection of the wound may also be compounded when a medical dressing is removed and portions of the dressing remain behind in the wound itself, particularly if the dressing is already colonized with pathogenic microbes. Thus, it is important that the dressing maintains its physical integrity when exposed to stress, such as during removal from the wound, in order to prevent additional complications and delays in healing.
Absorptive materials such as gauzes, hydrogels, swellable fibers, foams, woven textiles and the like have been incorporated into wound care devices for the purpose of controlling the wound moisture content. Fluids are generally absorbed by these types of materials by reversible capillary action or osmosis rather than by a one-way directional flow created by an inventive two-sided wound care device.
For example, U.S. Pat. No. 5,009,652 to Morgan et al. discloses a disposable laminated medical sponge that contains a thin film which is impervious to fluids and infectious agents. The medical sponge is designed to prevent the seepage of bodily fluids from one side of the sponge to the opposite side, since such seepage provides risk of infection for health-care workers having direct contact with patients.
U.S. Pat. No. 6,194,332 to Rock et al. discloses an antimicrobial composite fabric having a first inner fabric layer and a second outer fabric layer. The inner fabric layer may be comprised of polyester, acrylic or nylon fiber which has been rendered hydrophilic, such as by mechanical or chemical treatment. The hydrophilic inner fabric layer enables the transport of sweat from the inner fabric layer to the outer fabric layer. The fibers in the outer layer of the fabric may be blended with antimicrobial fibers in order to reduce the proliferation of bacteria in this layer. The fabric may be formed into a garment which provides reduced body odor. U.S. Pat. No. 6,602,811 to Rock et al. discloses a similar antimicrobial composite fabric, except that the second outer fabric layer also may be treated with an antimicrobial paste.
US Patent Application Publication No. 2004/0001880 to Bowler et al. discloses the use of gel forming fibers such as sodium carboxymethycellulose which can be incorporated into wound dressings. Silver ions may be incorporated into the fibers by combining them in a solution with a solvent prior to fiber formation. The dressing may be used as part of a larger dressing or a layer in a multi-layered dressing and need not be in direct contact with the wound.
The wound care device of the present invention takes advantage of a unique textile fabric construction which effectively isolates fluid away from the wound, which often results in improved healing. The differentiation that exists in a wound care device having a hydrophobic fiber on the wound contact side of the device and hydrophilic fiber on the fluid reservoir side of the device creates a unique one-way, directional flow of fluid and contaminants away from the wound.
A further feature of the wound care device of the present invention is that the device may also contain a topical coating of an antimicrobial agent such as silver. It is known that placing surface-available silver in contact with a wound allows the silver to enter the wound and become absorbed by undesirable bacteria and fungi that grow and prosper in the warm, moist environment of the wound site. Once absorbed, the silver ions kill microbes, resulting in treatment of infected wounds or the prevention of infection in at-risk wounds. Methods of topically applying a silver-based antimicrobial finish to textile substrates are described, for example, in commonly assigned U.S. Pat. Nos. 6,584,668; 6,821,936; and 6,946,433 and in commonly assigned U.S. patent application Ser. Nos. 09/586,081; 09/589,179; 10/307,027; and 10/306,968. All of these patents and patent applications are hereby incorporated by reference. Details of many of these processes will be discussed below.
The present disclosure addresses and overcomes the problems described above. Whereas, historically, a gauze or foam medical dressing has been applied to a wound with at least some intent on absorbing fluids, the present disclosure describes a wound care device capable of creating a one-way, directional flow of fluid and contaminants away from the wound, without detrimentally causing excessive dryness of the wound and substantial adherence of the device to the wound. The wound care device may additionally provide desired release of silver to the wound site for antimicrobial efficacy and, because of its unique construction, maintains its physical integrity when exposed to stress during ordinary use of the wound care device.
For these reasons and others that will be described herein, the present wound care device having unique fluid management properties represents a useful advance over the prior art.